1. Field of Invention
My invention relates to digital halftone compression and decompression, specifically to delineating variable-length runs using a “none-of-the-above” method.
2. Description of Prior Art
Digital halftone files have proven to be quite difficult to compress. Within the monochrome bitmap, each picture element, or pixel, is designated one of two “colors,” usually black or white. Due to the complexity of the image to be reproduced, the probability of any individual pixel being one color or the other is 50—50. This unpredictability affects the production of “runs,” large groups of pixels of the same “color.” Common compression methods based on run-length encoding prove inefficient, occasionally yielding “compressed” files even larger than the original input file.
Presently the digital halftone industry works around this problem by waiting until the last minute to create the monochrome bitmap. Complex image files utilizing a number of different file formats are compressed, stored or transmitted, and decompressed prior to being “rasterized” into a digital halftone file at the final output stage, the digital printer or monitor display.